BOSTON -- Ryan Lavarnway's first major league start at first base lasted less than five innings.

Lavarnway suffered a broken hamate bone (the bone that sticks out near the hand) in his left wrist when he fouled off a ball in his first at-bat of Thursday's game and is expected to miss a good chunk of the season.

"We'll know more after surgery," manager John Farrell said. "But at this point with four months remaining, I wouldn't expect it would be season-ending."

Lavarnway was due to get some chances at first base while Mike Napoli recovers from a dislocated finger on the 15-day disabled list, but the injury came at a bad time.

"There's never a good time for an injury," he said. "I'm disappointed right now, but hopefully it's nothing major and I can get back out there pretty quick."

To take his place on the active roster, the Red Sox recalled outfielder Alex Hassan to make his major league debut.

Hassan, 26 years old, grew up in Milton, Mass., went to Duke University and was drafted by the Red Sox in the 20th round in 2009. He has a .285 career batting average in the minors with a .393 on-base percentage, but has struggled offensively this season with Triple-A Pawtucket. He's hitting .217 with one home run and about one strikeout every three at-bats.

"There were some challenges during the season, but lately things have been going a lot better," Hassan said. "I've been feeling a lot better offensively and defensively."

Hassan was one of the few right-handed bats on the team's 40-man roster, and the only one available who can play first base. With Napoli out and Mike Carp battling a foot injury, the Red Sox need depth at the position. Daniel Nava can also play first base, though he's much better against right-handed pitching.

"We needed another right-handed bat," Farrel said. "The versatility is similar to Ryan's. In the addition of playing first base, (Hassan) can go to the outfield. He's moved around to two corner outfield spots as well as seven or eight games at first base. It's an opportunity for him to come and make his major league debut."